The invention concerns a ring cutter for cutting chips. Such a cutter has become known, for example, from DE 3,247,629 C1.
Cutters of this type are constructed as follows: the cutter comprises a ring of cutting knives. The ring of cutting knives, in turn, is comprised of a collar of knife packets. The knife packets are borne by two carrier rings, which enclose the knife packets between them. The ring cutter also has a rotor, which bears a multiple number of rotor blades.
Each knife packet contains the following components: a wearing [abrasion] plate, which is found in the region of the circular path of the rotor blades, a knife carrier, a clamping plate, as well as a knife clamped between knife carrier and clamping plate. For clamping, at least two fastening screws are used, which are arranged at a mutual distance in the longitudinal direction of the knife packet. Corresponding to the fastening screws, the clamping plate of the individual knife packet has borehole, the knife has a slot, and the knife carrier has a threaded borehole. The fastening screw is guided through the borehole in the clamping plate and the slot in the knife and screwed into the threaded borehole of the knife carrier.
The knives have only a limited service life of several hours. After this, they are worn out and must be changed for new knives. This means that the knife packets must be demounted. The fastening screws are unscrewed, the worn knives are removed, new knives are inserted, the clamping plate is again applied, and the fastening screws are guided through the boreholes in the clamping plate and the slots in the knives and are screwed into the threaded boreholes of the knife carrier. This involves the precise positioning of the knives and the clamping plate. In particular, the front position of the knife must be accurately adjusted, i.e., the radial position of the cutting edge. This process is time-consuming and requires great care and attention.
The clamping plate was previously attached by means of a guide slot and a pin engaged therein.
The object of the invention is to create a ring cutter of the type described initially, such that the knife packet can be easily and rapidly mounted with a position-precise clamping plate and position-precise knife.
Accordingly, the individual fastening screwsxe2x80x94together with the borehole in the clamping plate, the slot in the knife and the borehole in the knife carrierxe2x80x94are utilized for centering. In this way, a very considerable simplification is achieved in mounting, as well as a high adjustment precision of the knife involved.